How do I get my pipe command to accept options? - c++

Question

I am writing a shell for a class and I need to implement pipes. Right now my code works only when the first command does not use an argument. For example: 'ls | wc -l' works but 'ls -lt | head' does not.
void usePipe(string &command)
{
int fd_pipe[2];
int pid1;
int pid2;
int status;
int wpid;
string cmd1,cmd2;
stringstream ss(command);
vector<string> tok1,tok2;
char **cmd1c;
char **cmd2c;
vector<const char*>args1,args2;
pid1 = fork();
if(pid1 == 0)
{
getline(ss,cmd1, '|');
getline(ss,cmd2, '|');
cmd1 = reduce(cmd1);
cmd2 = reduce(cmd2);
cout << cmd1 << "|" << endl;
cout << cmd2 << "|" << endl;
tok1 = split(cmd1,' ');
tok2 = split(cmd2, ' ');
for(int i = 0; i < tok1.size(); i++)
{
if(tok1.at(i).c_str()[0] != '\0')
{
args1.push_back(tok1.at(i).c_str());
cout << "Pushed command: " << args1.back() << endl;
}
}
args1.push_back(NULL);
cmd1c =(char**) &args1[0];
for(int i = 0; i < tok2.size(); i++)
{
if(tok2.at(i).c_str()[0] != '\0')
{
args2.push_back(tok2.at(i).c_str());
cout << "Pushed command: " << args2.back() << endl;
}
}
args2.push_back(NULL);
cmd2c =(char**) &args2[0];
pipe(fd_pipe);
pid2 = fork();
if(pid2 == 0)
{
cout << "in second child" <<endl;
dup2(fd_pipe[1],1);
close(fd_pipe[0]);
close(fd_pipe[1]);
execvp(cmd1c[0], cmd1c);
perror("Exec Failed ");
exit(5);
}
cout << "in first child"<< endl;
dup2(fd_pipe[0],0);
close(fd_pipe[0]);
close(fd_pipe[1]);
execvp(cmd2c[0], cmd1c);
perror("Exec Failed ");
exit(5);
}
wpid = wait(&status);
cout << "Shell process "<< pid1 << " exited with status " << (status >> 8) << endl;
}

Answer 1

Found it. In the first child I was giving execvp the wrong arguments. It needed to be
execvp(cmd2c[0], cmd2c);